Huawei H12-831_V1.0 Exam With Confidence Using Practice Dumps

Comprehensive and Detailed In-Depth Explanation:

To determine which statements are false, we need to understand how OSPFv3 and IS-IS work together, and how Inter-Area-Router LSAs (Type 3 LSAs) are generated in OSPF:

1. Understanding OSPF Inter-Area LSAs (Type 3)

OSPF generates Type 3 LSAs (Inter-Area-Prefix LSAs) to advertise networks between areas.

Only Area Border Routers (ABRs) generate Inter-Area LSAs.

Type 3 LSAs allow routes to be advertised from one OSPF area to another (e.g., from Area 0 to Area 1 or Area 2).

2. Analysis of Each Answer Option:

✅ A. " R3 generates an Inter-Area-Router-LSA in Area 0. " → TRUE

R3 is an ABR (connecting IS-IS and OSPF Area 0).

Since R3 is importing IS-IS routes into OSPFv3, it must generate Type 3 LSAs to advertise those routes in Area 0.

This statement is correct.

✅ B. " R2 generates an Inter-Area-Router-LSA in Area 0. " → TRUE

R2 is also an ABR (connecting IS-IS and OSPF Area 0).

Like R3, R2 imports IS-IS routes into OSPFv3 and advertises them into Area 0 using Type 3 LSAs.

This statement is correct.

❌ C. " R1 generates an Inter-Area-Router-LSA in Area 2. " → FALSE

R1 is not an ABR.

Only ABRs generate Type 3 LSAs, and R1 is not an ABR between Area 2 and Area 0.

This statement is false.

❌ D. " R2 generates an Inter-Area-Router-LSA in Area 1. " → FALSE

Area 1 is a stub area, and stub areas do not allow Inter-Area-Router LSAs (Type 3 LSAs) for external routes.

R2 does not generate Inter-Area LSAs in Area 1 because OSPF prevents this in stub areas.

This statement is false.

OSPFv3 introduces Link-LSAs to advertise link-local addresses, IPv6 prefixes, and relevant interface options to routers connected to the same link.

Unlike Router-LSAs and Network-LSAs, a Link-LSA provides IPv6 addressing information associated with a particular interface.

In the displayed Link-LSA, the field Number of Prefixes has a value of 3. Three IPv6 prefix entries are listed: 2000:14::/64, 2001:14::/64, and 2002:14::/64.

The exhibit also includes a link-local IPv6 address beginning with FE80::. This address belongs to the link-local address space and must not be counted as a global unicast prefix.

Therefore, the intended examination interpretation is that the interface has three global unicast address prefixes.

Strictly, an LSA ' s prefix count does not independently prove the precise number of individual interface addresses, but among the provided options, D is the intended answer.

To determine the correct command, we need to analyze BGP behavior in a Hub-Spoke topology and how routes are advertised in MPLS VPN environments.

1. Understanding the Hub-Spoke BGP/MPLS VPN Topology

The network consists of Hub-PE and Spoke-PE routers, which are MPLS VPN PEs.

Hub-PE is responsible for distributing routes between Spoke-PE1 and Spoke-PE2.

Spoke routers do not have direct IBGP peering with each other; instead, they rely on the Hub-PE to relay routes.

BGP next-hop handling is critical for proper route advertisement.

2. Why is the " next-hop-self " Command Required?

By default, when BGP advertises a route, the next-hop remains unchanged (i.e., the original next-hop is retained).

In Hub-Spoke topology, Spoke routers would receive routes with a next-hop IP that belongs to another Spoke-PE, which is not reachable directly.

To solve this issue, we use the next-hop-self command on the Hub-PE, so that:

Hub-PE updates the next-hop to its own address before advertising routes to the Spoke-PEs.

This ensures that Spoke-PE routers use the Hub-PE as the next-hop, making routes reachable and preventing blackholing.

3. Correct Command Usage

The administrator must run the following command under the BGP IPv4 address family of the BGP-VPN_out instance on Hub-PE:

shell

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peer 10.1.2.1 next-hop-self

This ensures that the next-hop for advertised routes is changed to the Hub-PE ' s IP, allowing proper route transmission in the Hub-Spoke MPLS VPN environment.